How much bigger is a 65-inch TV than a 55-inch?

About 40% bigger by area (1,805 vs 1,293 square inches), because area scales with the square of the diagonal: (65 ÷ 55)² = 1.40. It is 18% wider and 18% taller. A 75″ TV has 86% more area than a 55″.

How do I work out a screen's width and height from the diagonal?

Divide the diagonal by √(1 + (W/H)²) to get the height, then multiply by W/H for the width. For 16:9, W/H = 1.778 and √(1 + 1.778²) = 2.040, so every 16:9 screen is diagonal ÷ 2.040 tall and diagonal × 0.872 wide: a 27″ monitor is 23.5″ × 13.2″, a 6.1″ phone at 19.5:9 is about 5.5″ × 2.6″.

Can I compare screens with different aspect ratios?

Yes — pick each screen's own ratio. The page then compares the two rectangles' width, height and area separately, which matters for ultrawides: a 34″ 21:9 monitor has 34% more area than a 27″ 16:9 monitor but almost the same height, so it is wider, not taller.

What sizes do the common aspect ratios give?

For the same diagonal, the closer a ratio is to square, the more area it has. A 27″ 16:9 panel is 312 square inches; 16:10 gives 328; 4:3 gives 350; a 27″ 21:9 gives only 264 because so much of the diagonal is spent on width. Enter the same diagonal with two ratios to see the difference.

What are the width and height of a 32, 43, 50 or 75-inch TV?

For 16:9 screens, the height is the diagonal × 0.4903 and the width the diagonal × 0.8716: 32″ is 27.9″ × 15.7″, 43″ is 37.5″ × 21.1″, 50″ is 43.6″ × 24.5″ and 75″ is 65.4″ × 36.8″, panel only.

Screen Size Comparison Calculator (TV, Monitor & Phone Dimensions)

Width, height and area of two screens from their diagonals and aspect ratios, and how much bigger one is.

Inputs

Screen A diagonal(in)

1 in200 in

Screen A aspect ratio

Screen B diagonal(in)

1 in200 in

Screen B aspect ratio

Include CalculateEveryday mark

Screen B vs A (area)

+39.7%

Viewable area A (sq in)1,292.6

Viewable area B (sq in)1,805.3

+39.67%

Screen A: 47.9″ × 27.0″ (121.8 × 68.5 cm), 1292.6 sq in
Screen B: 56.7″ × 31.9″ (143.9 × 80.9 cm), 1805.3 sq in
Working for A: height = 55.0 ÷ √(1 + (16/9)²) = 27.0″; width = 27.0 × 16/9 = 47.9″
Width, B vs A: +18.2%
Height, B vs A: +18.2%

Diagonal inches are the viewable panel, not the bezel. Same-ratio screens scale in area with the square of the diagonal.

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What each Screen Size Comparison input means

Screen A diagonal: The first screen's advertised size: the diagonal of the visible panel, in inches.
Screen A aspect ratio: Its width-to-height ratio: 16:9 for TVs and most monitors, 16:10 or 3:2 for many laptops, 21:9 for ultrawide monitors, about 19.5:9 or 20:9 for phones.
Screen B diagonal: The second screen's diagonal in inches. For sizes given in centimetres, divide by 2.54.
Screen B aspect ratio: The second screen's ratio. It can differ from the first; the page then compares the real rectangles.

Screen Size Comparison formula

height = diagonal ÷ √(1 + (W/H)²) · width = height × W/H · area = width × height · same ratio: area B ÷ area A = (diagonal B ÷ diagonal A)²

h = \frac{d}{\sqrt{1 + (W/H)^2}}, \quad w = h \cdot \frac{W}{H}

A screen's advertised size is its diagonal, corner to corner, and the width and height follow from the aspect ratio by Pythagoras: the diagonal is the hypotenuse of a right triangle whose legs are the width and height, so diagonal² = width² + height². Writing the width as height × (W/H) and solving gives the height, then the width, then the area. Two screens with the same ratio scale in area with the square of the diagonal ratio — which is why a 65″ TV is not 18% bigger than a 55″ but 40% bigger. With different ratios the comparison has to go through the actual rectangles, so each screen here has its own aspect ratio: a 34″ ultrawide monitor is only 1% taller than a 27″ 16:9 monitor but a third wider.

Screen Size Comparison worked example

A 55″ 16:9 TV: the ratio W/H is 16 ÷ 9 = 1.778, so the height is 55 ÷ √(1 + 1.778²) = 55 ÷ 2.040 = 27.0″ and the width is 27.0 × 1.778 = 47.9″ — an area of 1,293 square inches. A 65″ 16:9 TV works out at 56.7″ × 31.9″ and 1,805 square inches. That is 39.7% more screen, because (65 ÷ 55)² = 1.397, even though the diagonal is only 18% longer.

Where the Screen Size Comparison calculator can give the wrong answer

The diagonal is the viewable panel. Bezels, and on phones the rounded corners and camera cut-outs, are not in it, so the outside of the device is larger than the width and height shown.
The aspect ratio has to be the panel's real one. A 16:9 figure entered for a 16:10 laptop puts the height 5% out; ultrawides are 21:9 (strictly 64:27 or 43:18 on some models) and most current phones are around 19.5:9 or 20:9, not 16:9.
Area is not the same as usable picture. A 21:9 monitor showing a 16:9 video letterboxes it, so for that content only the 16:9 part of its area counts — compare a 34″ 21:9 to a 27″ 16:9 at the same height, not by area.
Metric sizes are the inch figures × 2.54. Some markets advertise TVs in centimetres of diagonal (a 140 cm TV is 55″); enter the diagonal in inches here.
Curved screens are measured along the curve, so their flat width is a little less than the figure shown.

Spotted a mistake? Tell us

Screen Size Comparison FAQ

: About 40% bigger by area (1,805 vs 1,293 square inches), because area scales with the square of the diagonal: (65 ÷ 55)² = 1.40. It is 18% wider and 18% taller. A 75″ TV has 86% more area than a 55″.
: Divide the diagonal by √(1 + (W/H)²) to get the height, then multiply by W/H for the width. For 16:9, W/H = 1.778 and √(1 + 1.778²) = 2.040, so every 16:9 screen is diagonal ÷ 2.040 tall and diagonal × 0.872 wide: a 27″ monitor is 23.5″ × 13.2″, a 6.1″ phone at 19.5:9 is about 5.5″ × 2.6″.
: Yes — pick each screen's own ratio. The page then compares the two rectangles' width, height and area separately, which matters for ultrawides: a 34″ 21:9 monitor has 34% more area than a 27″ 16:9 monitor but almost the same height, so it is wider, not taller.
: For the same diagonal, the closer a ratio is to square, the more area it has. A 27″ 16:9 panel is 312 square inches; 16:10 gives 328; 4:3 gives 350; a 27″ 21:9 gives only 264 because so much of the diagonal is spent on width. Enter the same diagonal with two ratios to see the difference.
: For 16:9 screens, the height is the diagonal × 0.4903 and the width the diagonal × 0.8716: 32″ is 27.9″ × 15.7″, 43″ is 37.5″ × 21.1″, 50″ is 43.6″ × 24.5″ and 75″ is 65.4″ × 36.8″, panel only.